mirror_ubuntu-kernels/kernel/trace
Florent Revest d9c9e4db18 bpf: Factorize bpf_trace_printk and bpf_seq_printf
Two helpers (trace_printk and seq_printf) have very similar
implementations of format string parsing and a third one is coming
(snprintf). To avoid code duplication and make the code easier to
maintain, this moves the operations associated with format string
parsing (validation and argument sanitization) into one generic
function.

The implementation of the two existing helpers already drifted quite a
bit so unifying them entailed a lot of changes:

- bpf_trace_printk always expected fmt[fmt_size] to be the terminating
  NULL character, this is no longer true, the first 0 is terminating.
- bpf_trace_printk now supports %% (which produces the percentage char).
- bpf_trace_printk now skips width formating fields.
- bpf_trace_printk now supports the X modifier (capital hexadecimal).
- bpf_trace_printk now supports %pK, %px, %pB, %pi4, %pI4, %pi6 and %pI6
- argument casting on 32 bit has been simplified into one macro and
  using an enum instead of obscure int increments.

- bpf_seq_printf now uses bpf_trace_copy_string instead of
  strncpy_from_kernel_nofault and handles the %pks %pus specifiers.
- bpf_seq_printf now prints longs correctly on 32 bit architectures.

- both were changed to use a global per-cpu tmp buffer instead of one
  stack buffer for trace_printk and 6 small buffers for seq_printf.
- to avoid per-cpu buffer usage conflict, these helpers disable
  preemption while the per-cpu buffer is in use.
- both helpers now support the %ps and %pS specifiers to print symbols.

The implementation is also moved from bpf_trace.c to helpers.c because
the upcoming bpf_snprintf helper will be made available to all BPF
programs and will need it.

Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210419155243.1632274-2-revest@chromium.org
2021-04-19 15:27:36 -07:00
..
blktrace.c block-5.12-2021-02-27 2021-02-28 11:23:38 -08:00
bpf_trace.c bpf: Factorize bpf_trace_printk and bpf_seq_printf 2021-04-19 15:27:36 -07:00
bpf_trace.h bpf: Use dedicated bpf_trace_printk event instead of trace_printk() 2020-07-13 16:55:49 -07:00
error_report-traces.c tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
fgraph.c fgraph: Initialize tracing_graph_pause at task creation 2021-01-29 15:07:32 -05:00
ftrace_internal.h x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up 2020-05-12 18:24:34 -04:00
ftrace.c ftrace: Fix modify_ftrace_direct. 2021-03-17 00:43:12 +01:00
Kconfig tracing: Fix help text of TRACEPOINT_BENCHMARK in Kconfig 2021-03-04 09:45:17 -05:00
kprobe_event_gen_test.c tracing: Add kprobe event command generation test module 2020-01-30 09:46:28 -05:00
Makefile tracing: add error_report_end trace point 2021-02-26 09:41:02 -08:00
power-traces.c
preemptirq_delay_test.c kernel: trace: preemptirq_delay_test: add cpu affinity 2021-02-02 17:02:07 -05:00
ring_buffer_benchmark.c sched,tracing: Convert to sched_set_fifo() 2020-07-29 11:43:53 +02:00
ring_buffer.c ring-buffer: Add a little more information and a WARN when time stamp going backwards is detected 2021-03-04 09:45:17 -05:00
rpm-traces.c
synth_event_gen_test.c tracing: Remove the useless value assignment in test_create_synth_event() 2020-11-13 12:19:52 -05:00
trace_benchmark.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_benchmark.h
trace_boot.c tracing: Disable ftrace selftests when any tracer is running 2020-12-14 12:05:03 -05:00
trace_branch.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_clock.c
trace_dynevent.c tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_dynevent.h tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_entries.h tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_event_perf.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_events_filter_test.h
trace_events_filter.c tracing: Clean up after filter logic rewriting 2020-11-16 12:32:34 -05:00
trace_events_hist.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_events_inject.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_events_synth.c tracing: Fix memory leak in __create_synth_event() 2021-03-04 09:45:57 -05:00
trace_events_trigger.c tracing: Fix event trigger to accept redundant spaces 2020-06-23 21:51:40 -04:00
trace_events.c Tracing updates for 5.12 2021-02-22 14:07:15 -08:00
trace_export.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
trace_functions_graph.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_functions.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_hwlat.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_irqsoff.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_kdb.c tracing: Rename trace_buffer to array_buffer 2020-01-13 13:19:38 -05:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c Modules updates for v5.12 2021-02-23 10:15:33 -08:00
trace_mmiotrace.c tracing: Remove definition of DEBUG in trace_mmiotrace.c 2021-02-02 17:02:07 -05:00
trace_nop.c
trace_output.c tracing: Show real address for trace event arguments 2021-02-11 16:31:57 -05:00
trace_output.h ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-09-14 10:08:07 +02:00
trace_printk.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
trace_probe_tmpl.h tracing/probe: Support user-space dereference 2019-05-25 23:04:42 -04:00
trace_probe.c tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_probe.h tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace_recursion_record.c ftrace: Add recording of functions that caused recursion 2020-11-06 08:42:26 -05:00
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-01-30 09:46:10 -05:00
trace_sched_wakeup.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_selftest_dynamic.c
trace_selftest.c tracing: Disable ftrace selftests when any tracer is running 2020-12-14 12:05:03 -05:00
trace_seq.c tracing: Remove unused TRACE_SEQ_BUF_USED 2020-01-21 18:39:54 -05:00
trace_stack.c ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs 2020-11-13 12:14:55 -05:00
trace_stat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.h tracing: Use generic type for comparator function 2019-11-14 13:15:11 -05:00
trace_synth.h tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace_syscalls.c tracing: Merge irqflags + preempt counter. 2021-02-02 17:02:06 -05:00
trace_uprobe.c tracing/dynevent: Delegate parsing to create function 2021-02-09 12:52:15 -05:00
trace.c tracing: Skip selftests if tracing is disabled 2021-03-04 09:51:25 -05:00
trace.h tracing: Remove duplicate declaration from trace.h 2021-03-04 09:44:47 -05:00
tracing_map.c tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00
tracing_map.h tracing: Fix some typos in comments 2020-11-10 20:39:40 -05:00